Drum latching mechanism for printing press



Feb. 2, 1965 L. MIASKOFE ETAL 3,

DRUM LATCHING MECHANISM FOR PRINTING PRESS 3 Sheets-Sheet 1 Filed June 25, 1962 INVENTORS.

,[g- L0NAR0 M/ASKOFF' BY FkmERlcK L. WARNER Feb. 2, 1965 L. MIASKOFF ETAL 3,

DRUM LATCHING MECHANISM FOR PRINTING PRESS Fi led June 25, 1962 s Sheets-Sheet 2 60 1 INVENTORS. .97" i; 44 ZEONARD M/ASKOFF 56 5 By flee-05mm L. WARNER NEY Feb. 2, 1965 L. MIASKOFF ETAL 3,

DRUM LATCHING MECHANISM FOR PRINTING PRESS Filed June 25, 1962 3 Sheets-Sheet 3 INVENTORS. LEONARD M/ASKOFF ylzimimc'k L. g am/5R A NE V United States Patent i 3,168,038- DRUM LATCHING- MECHANISM FOR PRINTING PRESS Leonard Miaskoff, Flushing, and Frederick L. Warner,

Brooklyn, N.Y., assignors, by mesne assignments, to

Fairchild Camera and Instrument Corporation, a corporation of Delaware Filed June 25, 1962, Ser. No. 204,853 Claims. (Cl. 101233) This invention relates to sheet fed printing presses and more particularly to means for separating the cylinders of a printing couple when the absence of a sheet is detected;

The need for a cylinder separating mechanism to space the cylinders of a printing couple when a sheet is not fed thereto is well understood in the art. Briefly, it is to prevent the transfer of an ink image from the printing cylinder to the impression cylinder since this transferred image would be subsequently offset to the reverse side of sheets thereafter printed. It is thus apparent that many sheets would be improperly printed due to the offset image on the reverse side thereof if provision is not made to separate the cylinders of the printing couple when a sheet is not feed therebetween.

Hereto fore, the arrangement of cylinder separating apparatus been to mount one of the cylinders eccentrically for movement into and out of engagement with the other cylinder. The cylinder so mounted is spring-biased towards a separated position but a latching mechanism is employed to maintain the cylinder in engagement with the other cylinder. A sheet detector mechanism also provided to respond to the absence of a sheet and move the latch member out of the path of the catch or detent so that the spring can pivot the eccentrically mounted cylinder out of engagement with the other cylinder. It is thus clear that the spring which is acting to separate the cylinders also is urging the members of the latching'mechanism into frictional contact one with the other. Consequently, before the latch member can be moved in response to the absence of a sheet, the force urging the catch or detent into contact with the latch member must be relieved. In the past this has been accomplished by a cam actuated lever that pivots the cylinder on its eccentric mounting against the force exerted by the aforementioned spring. Thus if the absence of a sheet is detected, the latch member can be moved out of latching position very easily without having to overcome a high friction force. The disadvantage of this arrangement is that the cam actuated lever relieves the aforesaid frictional force once during each machine cycle even when the cylinders are not to be separated.

The cyclical operation of the mechanism described has resulted in undue wear of components, particularly of blankets in offset printing presses. Moreover, noise and vibrations resulting from the pivoting of the cylinder into closer contact with the other cylinder in order to relieve the force between the members of the latching mechanism has been found objectionable particularly when the printing press is used in office type surroundings. The shortcomings of the prior art arrangement have been aggravated in the newer, higher speed presses.

A further disadvantage of the prior art arrangement for cylinder separation is that the cylinders, after being separated, were immediately brought back into engagement in preparation for the next sheet. If the sheet is not feed the cylinders are again separated so that if, for example, four machine cycles occur before sheets are again fed to the couple the cylinders will have been separated and engaged four times.

It is an object of the present invention to provide an A 3,168,038 Patented Feb. 2, 1965 ice improved cylinder separating mechanism wherein the normal relationship between the cylinders is modified when the cylinders are to be separated because the absence of a sheet is detected.

It is a further object of the invention to provide a mech nism wherein the cylinders will remain separated so long as the absence of a sheet is detected and will only re engage when a sheet is fed to the printing couple.

In carrying out the invention there is provided a mern her that is movable into and out of the path of a cam operated lever that relieves the force urging the catch or detent of the latching mechanism into engagement with the latch member. The arrangement is such that the movable member is projected into the path of the lever when the absence of a sheet is detected. After the cylinders are separated the member is again moved out of the path of the cyclically operating lever and remains out of its path until a sheet is detected at which time the member is moved into the path of the lever which thereupon moves the separated cylinder into engagement with the other cylinder.

More particularly, the eccentrically mounted cylinder is provided with a catch member having a catch or detent portion that is adapted to be engaged by a latch member which maintains the cylinder in printing relationship to the other cylinder. A spring is provided which urges the cylinder about its eccentric mounting in a direction to separate the cylinders. However, the engagement of the detent by the latch member prevents separation of the cylinders. The catch member also carries a pin which when projected is disposed in the path of a cyclically operated cam actuated lever which engages the pin to pivot the catch member against the force of the spring to thereby relieve the force urging the detent into engagement with the latch member and permit the latch member to be moved out of the latching position. The cylinders can then be separated by the spring. Ordinarily the pin is spring biased out of the path of the cam actuated lever so that the lever does not actuate the catch member. A cam is provided to project the pin into the path of the lever when the absence of a sheet is detected.

Features and advantages of this invention may be gained from the foregoing and from the description of a preferred embodiment thereof which follows.

In the drawings:

FIG. 1 is a side elevation view illustrating a two cylinder press and the cylinder separating mechanism of the present invention;

FIG. 2 is an enlarged end elevation of FIG. 1;

FIGS. 3 to 6 are enlarged fragmentary views of the I operating positions of the mechanism for releasing the latching finger preparatory to a cylinder separation operation;

FIG. 7 is an enlarged view of a cam, and its associated linkages, shown in FIG. 1; and

FIG. 8 is an enlarged view of a cam, and its associated linkages, shown in FIG. 1.

The drawings show a printing press of a two cylinder design wherein the arrangement includes a lower blanket cylinder 10 and an upper plate-impression cylinder 11. The feeding and delivery systems are arranged to feed the sheets from right to left as seen in FIG. 1. The sheets are fed from a conveyor belt 12 over a feed table 13 between the upper and lower feed rollers 14, through the bite of the printing couple, and out to a delivery area. The printing couple is composed of cylinders 10 and 11. The axes of rotation of these cylinders are disposed so that sheets can be fed in a substantially horizontal manner through the bite of the printing couple. Suitable Water and ink units, 15 and 16, are arranged adjacent to plateirnpression cylinder 11. While the embodiment shows a press across the feed table 13 which has a slot 18 formed therein. When a sheet has been correctly fed the-detector finger 17 will be supported thereby and the sheet will be fed into the bite of the printing couple. 7 In the absence of a sheet finger 17 will drop into slot 18 and be prevented from funther forward movement} As a result of this occurrence blanket cylinder will be moved to a posi-- tion out of engagement with cylinder 11.

The blanket cylinder 10 is rotatably mounted on a fixed shaft 19 which is eccentrically journalled in the side frames of the printing press. This cylinder is ro-' tated by a driving gear rotatably supported on one side frame of the press and connected to the blanket cylinder by an Oldham type coupling. The arrangement is such that when it is desired to move the blanket cylinder out of a printing position, the shaft 19 on which it rotates is pivoted on its eccentric mounting 20. The aforesaid driving gear is rotated by a motor and it in turn meshes with'a gear that is connected to the shaft 16 of plate-impression cylinder 11. For a more complete descriptionsof this mechanism see Patent No. 2,3 87,750.

A bell crank lever 22 pivotally mounted intermediate its ends at 22A carries a cam follower roller. 23, whichis urged into engagement with the periphery of cam 24 by the action of a spring 26.' The spring 26 secured at one end to the machine frame and at its other end to lever 22. Cam 24 has a nodal section 27 which engages follower noller 23 once for each revolution of the plate impression cylinder. The resulting action causes bolt 29 adjustably secured to the remote end of the bell crank lever 22 to reciprocate. Since cam 24is mounted on shaft 16, as is cylinder 11, lever 22 can be pivoted in timed relation to the printing cycle and a time delay can be effected between when the absence of a sheet has been detected and when'the printing cylinders are separated, thereby allowing the printing cylinders to finish printing of a preceding sheet before disengagement. A'catch member 30 is mounted on'eccentric mounting 20*an'd is formed with suitable adjustment slots through which bolt means 32 fixedly connect a disc .33 thereto. Disc 33 carries an adjustable 'stopbolt 34 designed to cooperate with car. portion 36 formed on member '30. Catch member 30 is formed with a detent portion, adapted to be engaged by a latching finger 38. A spring 40 fastened to disc 33 and the machine frame exerts a'resilient counter clockwise force tending to rotate the blanket cylinder about eccentric mounting 20. However, the engagement of catch member 30 and finger '38 prevents this Occurrence. When sheets are properly fed; a spring '42, which is connected between theremote end of finger 38 and the bell crank' 54, urges latching finger 38 clockwise 'into engagement with the detent in member "30. "In the absence of -a sheet bell crank 54 is pivoted counterclockwise, as will be explained hereinafter, and spring 42 exerts acounterclockwise force on latching finger 38 tending to move it out of engagement with member30. By the same counterclockwise movement of bell crank 54, a ducking pin 43 is projected'into the path of reciprocating bolt 29. Bolt 29 then engages the ducking pin 43 causing'member 30 to moveslightly clockwise. Latching finger38 under the urging of spring 42 then pivots counterclockwise until arrested by a stop member 44. At that moment the blanketcylinder 10 is urged by spring 40 to rotate counterclockwise on eccentric mounting 20 until the projection 36 of member 30 engages stop pin 45;

Ducking' pin 43 is mounted in an arm 47 carried by catch member 30 and is resiliently biased by a spring 48 into contact with a surface cam 50. Surface cam 50 is formed onbell crank 51, rotatably mounted on eccentric shaft20. Bucking pin 43 rides on surface cam; 50 and translates as it rides on the high and low sections thereof." When ducking pin -43--eri ag'es the high sections ofsurface cam 50, it is projected into the path of bolt 29. In the absence of a sheet, as seen in FIG.- 4, bolt 29 bumps ducking. pin 43 to rotate member 39 clockwise, thereby allowing the latching finger 38 to drop from its engaging position and the blanket cylinder 1 0 to tale about stub shaft 20 out of engagement with'the pl'a finpression cylinder 11. Blanket cylinder 10 returns' to ihengaging position when bolt 29 engages ducking pin {@g's'in 6 and moves it to a position as shown in FIG? a T his: occurs only when a subsequent sheet is detectedby de-' tector finger 17. At this time latching finger 3&5 is re; siliently returned to an engaging position with the defeat of latching collar member 30;

When sheets are fed in proper timed relation to the" printing couple, ducking pin 43 is biasedv out of the path of bolt 29 and can not be engaged thereby (see FIG. 3). In theabsence of a sheet, bell crank 51 is pivoted counterclockwise -to the position shown'in FIG. 4 to project pin 43 into the path of the reciprocating bolt 29 which causes the printing cylinders to separate as hereinabove described. When the printing cylinders are'in a disengaged position, arm 47 is inthe position shown in 5 and; ducking pin 43 again is biased out of the path of bolt .29. It is only when a subsequent sheet is properly ted that bell crank 51 is pivoted to the position shown in Fi .6 to project ducking pin 43 into the path of bolt 29, so as to return the printing cylinders roan engaging position. By bia in ducking in 43 m of the path of bolt 29ex= cept when'the printing cylinders new be separated of re-engaged for printing, the'pr esen't invention has ifec and associated problems that have characterized the art. he mechanism for controlling the operation of hell crank, 51 will now be described. Shafti 531i'sfsecufed in the machine frame and has bell crank 54 .rotatably mounted thereon. Bell crank 54 comprises two arms 55 and 56. Arm 55 has a push pull lever 57 pinned thereon, and at its remote end a fixed. pin 58 that has spring? 42 attached thereto. The other endof s ring 42 is at tached to latch finger 3.8 which is also rotatably mounted on shaft 53. As seen in FIG. 1 spring 42.normally urges latching finger .38 clockwise. However, if bell crank 54' is rotated counterclockwise, spring '42 will urge latching finger '38 downwardly or counterclockwise. Arm 56 has attached thereto spring 60 that constantly urges bell crank 54 in' a counterclockwise direction, .urging the push pull 'lever'resiliently upward. Arm 56 has rotatably mounted at its end rod 61 which in turn is pinned to bell V crank 51.

Crank 63 is pivotably mounted on the machine frame and has rotatably mounted: a-t itsremote end push=pull lever 57 by means of a pin 64. 'Pin'r64 asseen in FIG. 2 extends downwardly through push-pull lever 57 and crank 63 to a point slightly closer to the machine frame than a pin 65. Intermediate between the ends of crank 63 is va rotatably mounted cam follower 67 that is resiliently urged towards the periphery ofa cam 69 by the npward urging of push-pullgleve'r '57. A rocking lever 70 .is pivotably mounted intermediate betweenits ends on the machine frame and has a spring '71 fastened thereto urging a roller 72yinto engagement with a cam 74. Roller 72 is rotatablypinned to the upper side of'rocking lever 70 as seen in FIG, 2.

Cam 69 is keyed to a shaft 75 that is'journalled at both ends in the machine frame. Shaft :75 also has sprocket 77 and cam 74 fixedly mounted thereon. An endless chain 78 is trained over sprocket 77 and'a sprocket80, the latter: of which is mounted on shaft 16, thereby causing cams 69 and 74 to rotate at the same angular speed as plateimpression cylinder 11. The periphery of cam,74 com-- prises an arcuate sectionA extending through approxi" sta e 0 wh sh m e in ub emi wo ai line segments B and C which in turn merge into an armate section E of greater radius than section A. Cam 69 is constructed in a similar manner as cam 74 except that section A extends through approximately 60 and section E extends through approximately 250.

Detector finger 17 is pivotably carried on depending arm 81 which in turn is fixedly mounted on a shaft 82. Shaft 82 has keyed thereto a crank lever 83. This lever is located outwardly of the left hand support frame. Intermediate between the fixed and the remote ends of crank lever 83 is an extension member 85 upon which is secured member 87. Member 87 carries pin 65. The remote end of crank 83 has rotatably mounted thereon one end of a lever 89. The other end of lever 89 is rotatably mounted on the underside of rocking lever 70 below roller 72.

During operation when sheets are properly fed, detector finger 17 rides back and forth atop the feeding sheets. More specifically, between sheet feeding cycles, roller 72 rides on section B and roller 67 rides on section E of cams 74 and 69 respectively. When a sheet is fed roller 72 engages section B of cam 74 and causes sheet detecting finger 17 to ride forward. Pin 65 rotates clockwise and engages pin 64 preventing crank 63 from rotating. At a point in section B roller 67 disengages from the periphery of cam 69 and remains disengaged until cam 69 rotates to a point where in section C roller 67 again engages cam 69. During this operation crank 63 and push-pull lever 57 remain substantially stationary. As roller 72 engages a point in section C and moves to section E pin 65 withdraws from contact with pin 64 and sheet detecting finger 17 withdraws so as to be able to ride atop of the next feed sheet. As best seen in FIG. 3, bolt 29 will have reciprocated across the stationary bell crank 51 and latching collar arm 47 without engaging ducking pin 43. In the absence of a sheet detector, finger 17 lodges in slot 18 and is prevented from further forward movement, thereby preventing rocking lever 70 from rotating. Thereafter at a point in section B cam 74 disengages from roller 72. As a result of this action pin 65 is prevented from engaging pin 64 thus allowing roller 67 to remain in engagement with cam 69. When roller 67 engages section B, push-pull lever 57 moves upwardly. This causes bell crank 51 to be rotated to a position shown in FIG. 4 so that cam 50 projects pin 43 into the path of reciprocating bolt 29. When roller 23 engages nodal point 27, bolt 29 then bumps ducking pin 43 and latching finger 38 drops. Catch member 30 then rotates counterclockwise to a position determined by stop pin 45. At the same time bolt 29 withdraws to a position shown in FIG. 5. When roller 67 engages section C push-pull lever 57 is driven downward causing bell crank 51 to rotate to a position shown in FIG. 6. As roller 72 is again engaged by cam 74 at a point in section C, detector finger 17 is withdrawn from slot 18. On the next cycle if a sheet is fed bell crank 51 remains stationary and bolt 29 engages ducking pin 43 and rotates latching collar member 30 clockwise to a position shown in FIG. 3. This causes the printing cylinders to return to a printing relationship. At the same time latching finger 38 is urged by spring 42 into engagement with latching collar member 30. However, if a sheet is not fed, push-pull lever 57 is driven upwards and bell crank 51 rotates to a position shown in FIG. 5. Bolt 29 then reciprocates across bell crank 51 without engaging ducking pin 43. Bell crank 51 is then returned to a position shown in FIG. 6 when push-pull lever 57 is driven downwards. The mechanism is again ready for the next sheet feed cycle. The print couple cylinders by this arrangement remain in a disengaged position after a sheet has failed to feed until a subsequent sheet has been correctly registered and properly fed.

A sheet counting mechanism lever 95 is pivotably mounted on the machine frame and has a cam follower roller 96 that is urged into engagement with the surface of cam 97 by the action of spring 98. The other end of lever has a notched portion for engagement with a pin on a counter mechanism 99. When roller 96 engages the recessed portion of cam 97, lever 95 is caused to rotate clockwise and thereby actuate the counter mechanism 99. Connecting lever pivotably mounted at one end on catch 30 and at its other end on sheet counting mechanism lever 95 rotates lever 95 counterclockwise in the absence of a sheet, and disengages follower roller 96 from cam 97 thereby preventing any actuation of the counter mechanism 99. As can be seen in FIG. 1 connecting lever 100 is slotted to allow lever 95 to pivot clockwise without being hindered by connecting lever 100. When a job has been properly set up and the counter mechanism adjusted, no further attention need be given thereto as the counter will only register the number of sheets that have been printed.

It is to be understood that many changes could be made in the disclosed embodiment without departing from the spirit and scope of the invention and, therefore, the description and drawings are to be interpreted in an illustrative rather than a limiting sense.

What is claimed is:

1. In a sheet fed printing press having a first cylinderand a second cylinder which are separated in the absenceof a sheet and automatically engaged when a sheet is pres-- ent, cylinder separating means comprising eccentric mounting means for said first cylinder so that said first cylinder can be moved between a printing position and at non-printing position, a catch member secured to said' eccentric means, spring means for biasing said catch member to urge said first cylinder to a non-printing position, latch means to engage said catch member against the bias of said spring means to maintain said first cylinder in a printing position, means for biasing said latch means: into a non-latching position, means for detecting the ab sence of a sheet, a cyclically operated lever means, releasing means carried by said catch member and normally biased out of the path of said lever means, and additional means responsive to the detecting means detecting the absence of a sheet for projecting said releasing means into the path of said lever means whereby said lever means will engage said releasing means to pivot said catch member against the bias of the spring maintaining it in a latched position so that the latch means will be biased to a non-latching position and the spring means will urge said first cylinder to a non-printing position.

2. Cylinder separating means according to claim 1 wherein said additional means comprises a cam adapted to actuate the releasing means, means to operate said cam so as to move the releasing means into the path of the lever means, and wherein said detecting means is responsiv-e to the detection of a sheet to prevent said last named means from operating said cam to move the releasing means into the path of the lever means.

3. Cylinder separating means according to claim 2 wherein the cam is pivotally mounted with respect to the releasing means, the operating means includes a cam actuated linkage system connected to the pivotally mounted cam, and the detecting means includes a cam actuated linkage system that operates in timed relationship to the operating means linkage system.

4. Cylinder separating means according to claim 3 wherein the detecting means includes a member which blocks the operation of the operating means linkage system when a sheet is detected.

5. In a sheet fed printing press having a cylinder eccentrically mounted to permit the cylinder to be moved from a printing to a non-printing position when a sheet is not fed, cylinder separating means comprising a catch member secured to said cylinder and movable between a printing and a non-printing position, a latch member, means for moving said latch member into and out of latching engagement with said catch member, spring 'me'ans f orurging said catch member into a printing'pos'i tion in engagement with said latch member and into a non-printing position when said latch member is moved out 'o f"latching engagementwith said catch member, a cam opera-"ted lever which is cyclically operated and adapted .to move the catch member against the force of said spring means to relieve the frictional engagement between said catch member and said latching member so that the latter can be moved out of latching engagement preparatory to a cylinder separating operation and to restore said catch member to printing position after a cylinder separat ing operation, a pin membercarried by said catch'mem her but normally biased to aretracted position out of the path of said pivoting lever, a cam member for removing said pin member into the path of said. pivoting lever when the catch member is to be actuated by the pivoting lever, operating meansfor moving said cam member between a first and a second position, and sheet detector means for controlling said operating means.

6. Cylinder separating means according to claim wherein the cam member is'profiled to project the pin member into the path of .the pivoting lever when the catch member is in a printing position and said cam member is moved to its second position'in response to the absence of a sheet and when the. catch member is'in a nonprinting position and said cam member is moved to its first position in response to the presence of a sheet.

7. Cylinder separating means according to claim 6 wherein thecam member operating means includes linkage means and a continuously. rotating cam which causes said cam membcrto'inolve between its first and second positions;

' 8. Cylinder separating means according to claim 7 wherein the sheet'detector means includes blocking means which arrests the linkage. means to prevent movement of said" earn member to its second position when a sheet is detected. i I

9. Cylinder separating means according to claim 8 wherein the sheetdete ctor means includes a continuously rotating cam that periodically moves said blocking means intoand but of blocking position with respect to said linkage meansi. v

10, Cylinder separating means according to claim 9 including meansfor arresting movement of the blocking means to the blocking position when no sheet is fed whereby the cam member operating means moves said 'carn member to its second position.

References Cited in the file of this patent STATES PATENTS 

1. IN A SHEET FED PRINTING PRESS HAVING A FIRST CYLINDER AND A SECOND CYLINDER WHICH ARE SEPARATED IN THE ABSENCE OF A SHEET AND AUTOMATICALLY ENGAGED WHEN A SHEET IS PRESENT, CYLINDER SEPARATING MEANS COMPRISING ECCENTRIC MOUNTING MEANS FOR SAID FIRST CYLINDER SO THAT SAID FIRST CYLINDER CAN BE MOVED BETWEEN A PRINTING POSITION AND A NON-PRINTING POSITION, A CATCH MEMBER SECURED TO SAID ECCENTRIC MEANS, SPARING MEANS FOR BIASING SAID CATCH MEMBER TO URGE SAID FIRST CYLINDER TO A NON-PRINTING POSITION, LATCH MEANS TO ENGAGE SAID CATCH MEMBER AGAINST THE BIAS OF SAID SPRING MEANS TO MAINTAIN SAID FIRST CYLINDER IN A PRINTING POSITION, MEANS TO MAINTAIN SAID FIRST CYLINDER INTO A NON-LATCHING POSITION, MEANS FOR DETECTING THE ABSENCE OF A SHEET, A CYCLICALLY OPERATED LEVER MEANS, RELEASING MEANS CARRIED BY SAID CATCH MEMBER AND NORMALLY BIASED OUT OF THE PATH OF SAID LEVER MEANS AND ADITIONAL MEANS RESPONSIVE TO THE DETECTING MEANS DETECTING THE ABSENCE OF A SHEET FRO PROJECTING SAID RELEASING MEANS INTO THE PATH OF SAID LEVER MEANS WHEREBY SAID LEVER MEANS WILL ENGAGE SAID RELEASING MEANS TO PIVOT SAID CATCH MEMBER AGAINST THE BIAS OF THE SPRING MAINTAINING IT IN A LATCHED POSITION SO THAT THE LATCH MEANS WILL BE BIASED TO A NON-LATCHING POSITION AND THE SPRING MEANS WILL URGE SAID FIRST CYLINDER TO A NON-PRINTING POSITION. 